If the pump body contains the pressure regulator or
other valves, remove them and make sure they are free in
their bores. If the valves are sticking, they can be lightly
polished to free them. If the valves do not move freely after
polishing, replace the pump. Figure 17-35 shows a typical
valve and sleeve removed from the pump body. If the
valves in the pump have seals, replace the seals before
reinstalling the valves.
To reassemble a vane pump, begin by installing the
outer slide and the bottom vane ring. Then insert the vanes
in the vane rotor, Figure 17-36. The vanes must face in the
proper direction. Next, install the upper vane ring to hold
the vanes in position. Install the pressure regulator compo-
nents and then install the cover. Finally, torque the
fasteners to specifications.
To reassemble a gear or rotor pump, install the gears
in the proper order in the pump body. Be sure to install the
inner and outer gears so that any marks face upward. Then
place the pump cover over the pump body and install and
tighten the bolts in the order specified by the manufacturer.
Always use a torque wrench to tighten the bolts. If the
pump incorporates a clutch apply piston, replace the seals
as explained in the clutch pack rebuilding section and then
reassemble the pump as explained above.
Chapter 17 Rebuilding Automatic Transmissions and Transaxles 413
Measure
rotor end
clearance
Feeler
gauge
Straightedge
A Typical end clearance 0.001 to 0.003 in.
B Typical tip clearance 0.005 to 0.010 in.
C Typical side clearance 0.004 to 0.008 in.
Feeler
gauge
Measure
rotor tip
clearance
Measure
rotor side
clearance
Feeler
gauge
Figure 17-32. These three checks will determine whether the
pump can be reused. These checks apply to gear and rotor
pumps. Always refer to the service manual for wear speci-
fications. A—Checking the clearance between rotor or gear
faces and a straightedge laid across pump body (end clear-
ance). B—Checking the clearance between the tips of the inner
and outer rotor lobes or gear teeth (tip clearance).
C—Checking the clearance between the outer rotor or gear and
the pump body (side clearance). (DaimlerChrysler)
Hydaulic
press ram
Bushing
driver
Old bushing
Pump
body Press
bed
Figure 17-33. Worn pump bushings can be replaced with new
bushings. The old bushing is pressed out, as shown here.
Always check the service manual for exact specifications and
use the proper bushing removal and installation tools. (Ford)
Note: There are many variations in pump
design and placement.Three major types of
pumps are used. The pump may be placed
immediately behind the converter and driven by
converter lugs, or it may be placed in the valve body
and driven by a shaft. Due to these variations, only a
general outline of pump rebuilding can be given in
this chapter. Always consult the proper service
manual before rebuilding any pump.